Thermal Hydraulics and Reactor Safety

Research in thermal hydraulics and reactor safety encompasses studies of two-phase flow, heat transfer, phase change, coolant dynamics, liquid metal flow, magneto-hydrodynamics and various phenomena related to reactor safety. The laboratories that support this research are among the most extensive and best equipped among universities around the world.

Advanced experiments and models based on a mechanistic description of annular two-phase flow support advanced nuclear power systems. Separate effects experimental date along with special instrumentation support these models. For example, an advanced conductivity probe has been developed to measure atomization and deposition rate from liquid films under shear. These experiments and models are designed to develop a better understanding of critical heat flow (CHF) in nuclear reactors.

The School is a world leader in nuclear reactor safety for light water reactors. A broad range of reactor safety studies is carried out in the integral test facility PUMA and in extensive separate effects test facilities. Examples include the dryout of fuel rods, rewetting, two-phase flow instabilities, and the performance of various safety systems. Research computational tools include advanced two-phase flow models, numerical methods, multiphase computational fluid dynamics (CFD) codes, and graphical user interfaces.

Several well-equipped laboratories support research in thermal hydraulics and reactor safety:

The Nuclear Regulatory Commission established the Institute of Thermal-Hydraulics at Purdue University in 1997. The objective of the Institute is to provide broad technical expertise and perform thermal-hydraulics reactor safety research for the NRC. Areas of research include: modern code architectures and languages, advanced numerical methods, new two-phase flow models, constitutive models, graphical user interfaces, CFD, and fundamental experiments. Under the Institute, a team of internationally known experts have been assembled to carry out the research. This team is led by Purdue University and supported by seven other major Universities. The Institute is carrying out research to develop technology that results in dramatic improvements in existing accident analysis capabilities.

The Thermal-Hydraulic and Reactor Safety Laboratory (TRSL) consists of extensive experimental loops, reactor safety facilities and most advanced instrumentation systems supported by its own computer facility for studying nuclear thermal-hydraulics and two-phase flow. It contains six adiabatic two-phase flow loops, two boiling loops, one post dryout flow visualization loop and several reactor safety separate-effects test facilities. TRSL has three IBM RISC 6000 mini computers, a number of PCs, hot film anemometers, LDA, high speed video and movie cameras, EMBED Equation.3 -densito meters and other local two-phase flow instrumentations. The TRSL has research programs for international research scholars. The TRSL facilitates in advanced two-phase instrument development and calibration program. The laboratory is also supported by the attached machine shop and electronic shop.

Multiphase flow in channels and porous media, diagnostic and instrument developmental projects are carried out at a Multiphase and Fuel Cell Research Laboratory (MFCRL). The laboratory has programs in fundamental and applied research on multiphase flow and heat transfer. Development activities include simple and robust instrumentation for monitoring and control of the complex thermal-hydraulics processes. Projects on direct contact condensation, noncondensable effect on condensation, gas-liquid flow in packed bed, porous media and mini channels, microgravity two-phase flow, bubble dynamics in porous media, multiphase flow in fuel cells and novel flow field advanced fuel cells are carried out.

The PUMA (Purdue University Multi-dimensional Integral Test Assembly) facility located at Purdue University is the only existing U.S. Government integral test facility for boiling water reactors (BWRS). It is designed to simulate all thermal-hydraulic phenomena that may occur during design basis accidents and other transients in revolutionary innovative boiling water reactor designs with various passive safety systems. It simulates the reactor, containment, safety systems and control systems. PUMA is equipped with a state-of-the-art control room and 400 advanced instruments.